CA1206017A

CA1206017A - Plant-promoting preparations with controlled-start plant-promoting agent release

Info

Publication number: CA1206017A
Application number: CA000420173A
Authority: CA
Inventors: Robert Eibner; Michael Jaschkowitz; Hans-Paul Klepzig; Bernhard Kloth; Wilhelm Kohl
Original assignee: Schering AG
Current assignee: Bayer Pharma AG
Priority date: 1982-02-02
Filing date: 1983-01-25
Publication date: 1986-06-17
Also published as: IL67808A0; IE830190L; PH23687A; FI73958B; CH652708A5; DD208796A5; NL8204992A; DE3203849C2; ATA33683A; DK39783D0; IT1163028B; AT387769B; FI73958C; GB2116960A; DE3203849A1; ES8402806A1; AR231430A1; DK155728C; GB2116960B; IL67808A

Abstract

ABSTRACT OF THE DISCLOSURE

Novel fertilizer preparations with controlled-start nutrient release, the preparations containing the nutrient enveloped in an enveloping agent selected from water-repellent substances, substances that are sparingly soluble in water and substances capable of swelling in water, and the use of such fertilizers. The fertilizer preparations have a delayed-start nutrient release, the time of which can be controlled according to the desired purpose for which they are used.

Description

~2~

ri~he present invention relates to nutrient ~ertili-zer preparations with controlled-start nutrient release, and with their use.

As is known, fertilizers are substances for feed-ing to cultivated plants in order to promote their growth, increase their yield, or improve -their quality.

All known solid fertilizer preparations make nu~
trients available to the plants by way of the soil and/or substrate solu-tion according to the speed with which they dissolve. The state of the ar-t is to co.ltrol the speed at which they dissolve in such a way that the nutrients can flow uniform:Ly according to the composition of -the Eertilizer preparation during a selected period of time, Erom the time of application onwards.

A common ~actor with all these fertilizers, however, is that the start of the nutrient release cannot be con-trollecl, so that fast-acting fertilizers release the whole of the amo~m~ of the nutrients immediately and the slow-act:Lng fertilizers liberate a part of the amount of the nutrients immediately.

For physiological, ecological and economic reasons it is desirable and/or necessary to increase thè utilisation of fertilizer prepara-tions, and thus their effectiveness, in such a way that wi-th a single high total outlay and thus with the lowest possible application cost both phy-totoxicity and pollution due to leaching-out losses are avoided or at least reduced to a great exten-t.
;

The present invention provides a fertilizer pre-paration which makes the nutrients available only at a desired time and in the required amounts.
,~y~

~2~ 7 The present lnvention provldes a Eertilizer with controlled start of nutrient delivery, comprising nutrients which are enveloped wlth a water-rejecting substance selec-ted from the group consisting of paraffins, waxes, metal soaps, quaternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic compounds, a substance sparingly soluble in water or a water-swelling substance.

The present invention also provides in a method for the control]ed delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the above fertilizer whereby the nutrient flow first begins after a waiting period of Erom 30 up to 180 days.

The fertilizers have a delayed-start nutrient release, the time of which can be contro]led according to -the desired purpose for which they are used by the choice of the enveloping substance.

Particular embodiments oE the fertilizers of the present invention are that: the plant nutrient is a mineral single nutrient fertilizer, a mineral fertilizer containing two or more nutrients, an organo-mineral fertilizer, an organic fertilizer, a -trace nutrient or a combina-tion of two or more such subs-tances, the nutrient is a fer-tilizer in -the form of a powder, a crys-talline fer-tilizer, a granular fer-tilizer, a fertilizer in the form of coated granules, a fertilizer in the form of rod-shaped pelle-ts, an encapsulated fertilizer solution or an encapsulated fertilizer suspension, the nutrient is a fertilizer containing at least one nutrien-t selected from the elements carbon, oxygen, nitrogen, ~Z~6~.7 phosphorous, ~otassium, magneslum, calcium, sulphur, iron, manganese, copper, zinc, chlorine, boron, molybdenum, sodium, silicon, cobalt and aluminium, the or each element preferably being present in the form of a compound, the enveloping substance is at least one water-repellen-t substance selected from paraffins, waxes, metal soaps, quaternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic com-pounds, the water-repellent substance is iron palmitate, the enveloping substance is a substance that is sparingly soluble in water or capable of swelling in water, the sub~
stance being a polymer containincJ water-wettable grQupS, the water-wettabLe groups are hydroxyl, carboxyl, alkyl ester, cyano, chloro or fluoro groups, ~0 such polymers that are sparingly soluble in water or capable oE swelling in water are polyvinyl alcohols, preferably containing a residual ace-tyl con-tent of 1~%, the enveloping substance is a substance that is sparingly soluble in water, the substance being an inorgan~c compound, 3~, 61~7 such an inorganic compoun~l that is sparingly soluble in water lS iron phosphate or calcium phosphate, the enveloping substance i5 (i) a substance that is sparingly soluble in water or capable of swe]ling in water, the sub-stance being a polymer containing water-we-ttable groups or an inorganic compound, and (ii) at least one water-repellen-t substance selected from paraffins, waxes, metal soaps, qua-ternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic com-pounds, the enveloping agent is a water-repellen-t substance, the layer of the water-repellent substance surrounding the nutri.ent having a thickness within the range of Erom 10 8m to l.0 2m, preferably from 1 . 10 6m -to 2 . 10 3m, the enveloping subs-tance is a subst;ance that is sparingly soluble in water or capable of swelling in water, the layer oE the enveloping substance surroundint~ -the nutri.ent having a thickness within the ran~e of from 10 6m to 10 2m, pre-Eerably from 5 . 10 5m to 2 . 10 31n.

:~5 ~ 4 ~

i ~2~6~7 The fertilizer preparations according to the pre-sent invention have, surprisingly, a nutrien-t release which starts after a time lag and the start of which can be con-trolled according to -the desired purpose by the choice of an appropriate enveloping agent, so that the flow of nutrients does not begin until a delay -time of, for example, from 1 day to 2 years, preferably frorn 30 to 180 days, has elapsed.

The envelopi.ng substance may thus be a substance capable of releasing the nutrient, for example a fertilizer, within a period of from 1 day to 2 years, pre-ferably from 30 to 180 days, after the pre-].5 ~Z'~60117 E)aratiol~ of the present invention has been introduced into soil.

Many advantages which cannot be obtained by the use o~ Lhe hitherto known fertiliser preparations result from this con-trolled nutrient release.

Thus, fox example, fertilisinc3 can be carried out according to actual requirernents, with -the nutrient release being adjustecl to meet the peak requiremen-t and the zero requirement oE the plants, and this is not possible with any of the previously known fertilisers.

By this means -the varying nutrient requirements of plants during a cultivation period can be met to the optimurn, this of course being an advantage; thus damage to the plants due to over-Eertilising during periods oE high plant sensitivity, or insufficieot growth due to all inadequaie supply of nutrients when requirernents are at a rnaximum can be avoided.

The enveloping substrate may thus be a subs-tance capable of controllin~ the release of -the nutrien-t in a way suited to the nutri~nt requirements of the plant to be treated with the preparations of the present invention, so that over-fertilising and/or unacceptable lPaching-out losses are avoided.

The liberation o~ the nutrient supply which can be controlled by means of the fertiliser preparations O 7 ..
according to th~ pregent i~vention al~o o~era the ad-vantage of fully reall~ing the yield pot~ntial o~ pl~nts ev~n und~r un~avo~rable climatlc co~ditions or on 90~1 with poor ~ertilityD thu3 opening up avenues for hi~h performance fertilislng which were previously not poB~i-ble.
~ urthermor~, the liberation o~ thc ~ut~ie~t flo~
which can be controlled by means o~ the ~ertiliser pre-paratlon~ according to the prese~t inYe~tion o~fer~ th~
po~sibi:Lity o~ sati~ying to an optimum degre~ the changinig demands with regard to nutrient ~orm~ ~nd th~lr conce~tration ~or a speciaL cultivstlon b~ mean3 of a gi~gle total ~uantit~ o~ fertiliser applied at ~owing time vr when potting, so that ri~ky ~ollow-up fertili~ing, which i~ ine~ecti.Ye when carried out at the wrong time, can be o.mittedO
The liberation of the nutrle~t supply whlch can be controlled by me~n~ oi the *er~ ser prepar2tions according to the pre~ent invention ~lso o~ers the pos~ibility o~ addin~ ~ertillser~ to ~ub~trate~ long be~ore the latter are u~ad ? without haYing to ta~e into account hlgh salt contents that are already activ~ when use i~ commenced~ s~nce they are ~irst activated b~
wateri~g ~ the ~ub3trates when their use commence~ 80 that salt sho~k and/or salt damage can be avoided~
sc~ ~strc~te ~B ~h~y the en~velop~ng ~g~ ma~ be a ~ubYtanc~

3~

capable of releasi.ng the nutrient, after watering of a sub-strate to which ~he preparation vf the present invention has been added.

The following fertilisers may be used as the nutrient in accordance with the present invention: fertili-ser powders; crystalline fertilisersi granular fertilisers;
granular coated fertilisers; fertilisers in -the form of rod-shaped pel:Lets or encapsulated fertiliser solu-tions or suspensions.

The above-men-tioned fertilisers may be: mineral single nutrient fertilisers; mineral multi-nutrient fer-tilisers; organo-mineral fertilisers; organic fer-tilisers, trace nutri.ents or combinations of the above-mentioned com-ponellts.

As the nutrient there may also be used fertilisers that have ~een subjected to any pre-treatment, for example fertili.sers with a retarded reLease of the plant nutrients, amotlg which sparingly soluble sa].ts, polymeric nutrient compounds and nutrients chemically or physically ~ound to natural and synthetic carriers may be mentioned by way of example.

~2''~6~

The present invention also provides a method of pro~oting the development of a living plant, wherein the area in the vicinity of the living plant is treated wi,h a preparation of the present invention.

The present invention further provides a method of promoting the development of crop plants in a crop area, wherein the crop area is treated with a preparation of the presellt i.nvention. As i.ndica-ted above, a single treatment o:E the crop area may be carried out at the start of the crop plants' growth with an amount of the preparation that is sufficient for the crop plants until they are fully deve-loped; another possibility is for the treatment to be carried out beEore the crop plants are sown in the crop area.

The present invention further provides a pack which comprises a preparation of the present invention, together with instructions for its use for promoting the development of plants.

The present invention further provides a pxocess for the manufacture o~ a preparation of the present inven tion, wherein in a suitable appara-tus a nutrien-t is enve-loped su~ficien-tly uniformly with a layer having a suitable thickness of an envelop.ing substrale, tne enveloping substrate being selected from water-repellent substances, substances ~hat are sparingly soluble in water and substances capable of swelling in water.

a~

This process of the present invention may be carri.ed out in a manner known per se, for example, by placing the nutrient in an apparatus suitable for the type of -treatmellt in questi.on, for example in a rotating drum, a granulating vessel or a revolving coating apparatus, and adding the appropriate treatment agent thereto in such a way that the nutrient is enveloped completely and in a suf-ficiently uniform manner to the desired layer thickness, or by placing the appropriate treatment agent in a suitable apparatus, for example in a rotating drum or a granulating vessel, and introducing the nutrient in such a way -that the nutri.ent is enveloped completely and in a sufficiently uniform manner to the desired layer thickness.

1.5 As the water--repellent substances, substances that are sparingly soluble in water and substances capable of swelling i.n water ~om which the enveloping subs-tance is selected, there may be mentioned ihn ~?articular those listed in the followi.ng Table~

6~ 7 Tabl~ I
Paraffins, advantageou~ly wit~ a melting range between 40 and 250C~ prefarably hard para~ with a melt~ng r~ng~ o~ more ~h~n 55C;
wa~es/ ~or e~ample bee~wa~t spermaceti and carnauba wa~;

metal soaps~ ~or example Mg-, CB_, F~-7 CU-, 2n-, Mn-, Zr- or hl-8alt8 of la~ric acid~ myriBtiC acid~ palmitic acid, s1;earic acid or oleic acid, preierably Mg , Ca-, ~e-, ~ or Zr-salts oi palm~tic acid, quater~ary ~mmonium compou~d~, ~or e~ample ootadeoyloxy~
methylp~r1d~nium chloride or ].~-methyl~-stearoylamido-methylenep~ridinlum chlorid~
~atty acid-modi~ied ~ynthetic resins~ for e~mplo con-densate3 of monododecylurea-~ormaldehyd&-preconce~tratc or hexamethylolme~mine ether modi~ied with lauric aei~
palmitic acid and~or stearic acid 9 urea deri~ative~ ~or e~m~le octadecylethyleneurea;
melami~a derivative~
polysilo~anes~ ~or e~ample hydroge~ methy~ polysilo~ane

2~ and dimethyl poly~lo~ane;

fluorocarbon polymerisate~, ~or e~ample l,l-dihydro-pergluoroctylpolyacr~lic acid ester;
alginate~9 for e~ample potassium al~nate;
ge~at~ns~o ca~ein, poly~accharide~ for e~ample ~tarch, lactos~ c~llulose, cellulose derivative3, ~or exampl~ ethyl cellulos~, hydro~ypropyl cellulose and mi~ture~ thereo~ pectins 5 a~d ~anthans~
polyvinyl alcohol~;
polyvinyl aoetate~;
poly~i~yl eth~rs;
polyvinyl pyroll~dones;
polyacrylate~;

clay mlnerals~ for e~ample b~tonit~, illite and ~tta-pul~lt0;
metal o~ide~ ~or esample iron o~id~ hydrate and mag ~e~ium o~ide;
metal phosphate~ for e~ample caloium phosphate and iron pho~phate;
polyphosphates, for example ~urrol's ~alt and metal ~il1c~te~, ~or examp~e potash water gla~ (potas 8ium ~ilicat~.

0~ the ~ubstance~ listed in Table I there are preisrably u~ed as the enveloping agent partially ~apo~i~ied polyvinyl acetates~ gelatin~ ~ron o~d~
hydrate~ and calcium phosph~t~.

z~

- ~3 ~

~ he layer oi ~elop~ng agent 1~ generally applied in a thicXne~s o~ irom 1~ ~m to 10 2m7 e~p~cially ~ro~
1 . 10 ~m to 2 n 10 3m.
The plant-promoting preparations o~ the press~t 5 invention may be applied alone~ or in ~olution or a~ an emul~ion and al~o comblned ~ith othar substances a~ part of multi~compone~t sy~tems~
The follo~ing ~xample~ illustrato the iavention:

2~i7~5 g o~ a~ ~P~-synthe~lzed granulate ha~ing a nutrie~t compo~1tlon oi 13-1~5~21 and a particl~ ~iza range o~ from Z.0 ~ 400 mm w~3re heated to 100 ~ 110C
wi~h hot air in a rotating d~lm. With hot air ¢ontinu-ing to b~ introduced, there waY added to th~ granules a total of 48 g o~ a 2~ strength ~uspen~ion conai~ting o~ 9 parta of a binding agenlt baeed o~ a~ oil-modl~ied alkyd resin with 1 part o~ iro~ palmitate ln a ~olve~t mi~tur~ composed o~ 1 part O~e ben~ino haYing a bolli ng range o~ ~rom 130 to 220a and ~ Fart~ o~ xylene, i~
~uch a ~a~ that the do~ng and drying ~ate~ of the ~u~pen~ion w~re the same~ ~hen the treatment had been comple~ed, the granules were 910wly cooled to roo.
tempera~ureO
~a~
475 g o~ an ~PE-chlp ~r~nulate produced with 100 g ::lL2~

o~ ~ 50% ~re~,gth alkyd re~in 9011~tiO~l a~d ha~ring a nutrlent compo~ition oi 18-4,,5-9~t:.9 MgO-O~ and having a particle 8ize raIlge vf from 3"0 to 5.0 mm wer~
heated to 50-50 with hot a~ r ~n a coating d~ac, Wlth 5 the rlow of hot air bein~ maintained ~500 l/minute~, there wa~ added to the granules a total of 250 g OI a 109~ aqueous pol~inyl alcohol solution ~residual acetyl contellt appro:simately 10%9 vi~co~ty at 20C appro~
mately 35 mPas) ~ such a w~r that the do~inLs a~d dr~y-ing rates ot the solutio~ were the ~ame. Whe~ thetreatme~t ~ad been completed, 810Y cool~g to room temperl~ture wa~ carried outv ~am~le ~
425 g o~ a ~ertiliser produeed from 38~ g o~ an NP~chip ~ranulate and 85 g of a 5~ ~tre~gth alkyd re~n ~olution ~nd hav~ng a ~utrient composition o~
18-405-9-O.9 MgO-O,l Fe and ~having a particl~
ra~g~ of from ~vO to 5.0 mm T~ere heated to 50 to 60~
by hot air ~n a coati~g drum having a periorated base.
With the ~low o* hot air bein~ maintained, there was slowly added to the gran~les a total of 500 g o~ ~
10~ aqueou3 pol~vinyl alcohol solution (residual acetyl conte~t appro~imately 10%, vi~cosity at 20C appro~l-mately 35 mPa~3, ~n ~uch a ~ay that the do~ing and dryl~g rate~ o~ the 901ut~ 0~ ~ere th~ ~ame. ~ter 1 2~D0 ~ 7 ~his coating had ~e~n completed, the granules wereheated ~o 110 to 120~a and 25 g o~ a pre-cross~linked methyl~ilo~ane-hardener mi~ture ~ere added thereto i~
such a way that the dosing and harden~g rate~ of thc S m~tura were aga~n the same. When the treatment h~d bee~ completed 9 the produc~ wa~ 6iowly coolçd to roo~
temperatureO
The ~ollowin~ ~amples illu3trate the use of fert~liser preparation~ accordlng to the pre~ent i~-1~ ~ention. and their e~ect~ as comp~red with knQwn agents.
E~a~. ~
The tim~-dependent nutrie~t release characteristlc~
Or the ~er~iliser gran~Lles identi~ied in the Tabl~ be~
low in wa-ter were determined by contlnuou~ mea3urement Or kh~ oonduotivity of the dissol~ed 8alt9 accumulating in the watsr~ ~he r~ults are li~ted in the TableO

Tims&ranule~ treated Granule~ treated with aIkyd re~in ascording to Example 20 (min~ cm~ /c~
O O
2~ 0 ~ ~7 0 ~ 107 r3~3~

Time Granule~ treated ~ranules treated w~th al~yd resi~ accordlng to ~amp~ 3 ~mi~) ~ ~ ~cm) (~cm) 1~ 123 1~ 14~ 2 .~8 156 3 ~2 16~ ~
17~i ~ 7 26 18~ 12 28 18Ci 20 ~0 19~ 31 .~
The t~me-depende~t nutri.ent reles~ characteristics o~ the fertil~ser granule~ identi~ied i~ the Tabl~
below ~ a substrate were de~ermined by measureme~t o~
2~ slngle out yield8 o~ meado~ grass dry matter over a period of 8Q day~ ~ter a single applicatio~ o~ do-pressivelyracti~g fertili~er m~ed lnto the ~ubstrat~
before the meadow gras~ was ~own. The results ar~
listed in the Tab~e~
~The control value used to obtain the re~ults ~ ed i~ the Tabl~: the measurement taken wlth a ~ubstrate having a ~od, ~at~aral nutrient 3upp~ wlth-cut deprea~ivel;y~act~ fert:Lliser mi:2~ed in was ~ake a~ eq~ to 100% 3 .

~ime betwee~ L~ fertillser 1~13-21 __ _ . _ 5 ~owin~ date without ~ith alkyd treated accurd-and Cllt ting after res1 n treat- ing tQ inventio treatment ment E18 i31 ~Xalllple 5 date ~0 ~ ~ %
~day~
, 0 ~ 5 2~ ~ 7~
E~ 49 109 5~ 43 111 191 ~0 72 18B ~1~

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fertilizer with delayed start of nutrient delivery, comprising nutrients selected from the group consisting of carbon, oxygen, nitrogen, phosphorus, potassium, magnesium, calcium, sulfur, iron, manganese, copper, zinc, chlorine, boron, molybdenum, sodium, silicon, cobalt, aluminium and compounds thereof, said nutrients being enveloped with enveloping means consisting essentially of water-rejecting substance selected from the group consisting of paraffins, waxes, metal soaps, quaternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic compounds, a substance sparingly soluble in water or a water-swelling substance, whereby when the fertilizer is placed in the earth the nutrient flow first begins after a waiting period from 30 up to 180 days.

2. A fertilizer as claimed in claim 1, wherein the or each element is present in the form of a compound.

3. A fertilizer as claimed in claim 1, in which the nutrient is a mineral single nutrient fertilizer, a mineral fertilizer containing two or more nutrients, an organo-mineral fertilizer, and an organic fertilizer, a trace nutrient or a combination of two or ore such nutrients.

4. The fertilizer as claimed in claim 1, in which the nutrient is a powder fertilizer, a crystalline fertilizer, a granular fertilizer, a coated granule fertilizer, a rod-shaped pellet fertilizer, an encapsulated fertilizer solution or an encapsulated fertilizer suspension.

5. A fertilizer as claimed in claim 1, wherein the enveloping substance is at least one water-repellent substance selected from paraffins, waxes, metal soaps, quaternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic compounds.

6. A fertilizer as claimed in claim 5, wherein the enveloping substance is iron palmitate.

7. A fertilizer as claimed in claim 1, wherein the enveloping substance is a substance that is sparingly soluble in water, the substance being a polymer containing water-wettable groups.

8. A fertilizer as claimed in claim 1, wherein the enveloping substance is a substance capable of swelling in water, the substance being a polymer containing water-wettable groups.

9. A fertilizer as claimed in claim 7, wherein the water-wettable groups are hydroxyl, carboxyl, alkyl ester, cyano, chloro or fluoro groups.

10. A fertilizer as claimed in claim 8, wherein the water-wettable groups are hydroxyl, carboxyl, alkyl ester, cyano, chloro or fluoro groups.

11. A fertilizer as claimed in claim 7, wherein the polymer is polyvinyl alcohol.

12. A fertilizer as claimed in claim 10, wherein the polyvinyl alcohol contains a residual acetyl content of 10%.

13. A fertilizer as claimed in claim 1, wherein the enveloping substance is a substance that is sparingly soluble in water, the substance being an inorganic compound.

14. A fertilizer as claimed in claim 13, wherein the inorganic compound is iron phosphate or calcium phospate.

15. A fertilizer as claimed in claim 1, 2 or 3, wherein the enveloping substance is (i) a substance that is sparingly soluble in water or capable of swelling in water, the substance being a polymer containing water-wettable groups or an inorganic compound, and (ii) at least one water-repellent substance selected from paraffins, waxes, metal soaps, quarternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorinated organic compounds.

16. A fertilizer as claimed in claim 1, 2 or 3, in which the enveloping substance is selected from paraffins with a melting range between 40 and 250°C, waxes, metal soaps, quarternary ammonium compounds, fatty acid-modified synthetic resins, urea derivatives, polysiloxanes, fluorocarbon polymerisates, alginates, polysacchrarides, clay minerals, metal oxides, meal phosphates, polyphosphates and metal silicates.

17. A fertilizer as claimed in claim 1, 2 or 3, wherein the enveloping substance in selected from hard paraffin with a melting range of more than 55°C; beeswax, spermacti wax, carnauba wax; Mg-, Cas-, Fe-, Cu-, Zn-, Mn-, Zr- or Al-salts of lauric acid, myristic acid, palmitic acid, steric acid or oleic acid, perferably Mg-, Ca-, Fe-, Al- or Zr-salts of palmitic acid; octadecyloxymethylpyridium chloride, N-methyl-N-stearoylamidomethylenepyridium chloride; condensates of monododecylurea-formaldehyde-pre concentrate, hexamethylolmethylamine ether modified with lauric acid, palmitic acid and/or stearic acid;
octadecylethyleneurea; melamine derivatives; hydrogen methyl polysiloxane dimethyl polysiloxane;
1,1-dihydroperfluoroctylpolyacrylic acid ester; potassium alginate; gelatins; casein; starch, lactose, cellulose, cellulose derivatives, pectins xanathans; polyvinyl alcohols; polyvinyl acetates; polyvinyl ethers; polyvinyl pyrollidones; polyacrylates; bentonite, illite, attapulgite;
iron oxide hydrate, magnesium oxide; calcium phosphate, iron phosphate; Kurrol's salt and potash water glass (potassium silicate).

18. A fertilizer as claimed in claim 1, wherein the enveloping substance is a water-repellent substance, the layer of the water-repellent substance surrounding the nutrients having a thickness within the range of from 10-8 to 10-2m.

19. A fertilizer as claimed in claim 18, wherein the thickness is within the range of from 1.10-6m to 10-3m.

20. A fertilizer as claimed in claim 1, wherein the enveloping substance is a substance that is sparingly soluble in water or capable of swelling in water, the layer of the enveloping substances surrounding the nutrient having a thickness within the range of from 10-6m to 10-2m.

21. A fertilizer as claimed in claim 20, wherein the thickness is within the range of from 5.10-5m to 2.10-3m.

22. A fertilizer as claimed in claim 1, 2 or 3, wherein the enveloping substance is a substance capable of releasing the nutrient after watering of a substrate to which the fertilizer has been added.

23. A process for the manufacture of a fertilizer as claimed in claim 1, 2 or 3, wherein in a suitable apparatus a nutrient selected from the group consisting of the elements carbon, oxygen, nitrogen, phosphorous, potassium, magnesium, calciuim, sulphur, iron, manganese, copper, zinc, chlorine, boron, molybdenum, sodium, silicon, cobalt and aluminium is enveloped sufficiently uniformly with a layer having a suitable thickness of an enveloping substance, the enveloping substance being selected from water-repellent substances selected from the group consisting of paraffins, waxes, metal soaps, quaternary ammonium compounds, urea derivatives, fatty acid-modified resins, silicones and perfluorillated organic compounds a substance sparingly soluble in water or a water-swelling substance.

24. In a method for the controlled delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the fertilizer according to claim 1, 2 or 3, whereby the nutrient flow first begins after a waiting period from 30 up to 180 days.

25. In a method for the controlled delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the fertilizer according to claim 4, 5 or 6, whereby the nutrient flow first begins after a waiting period from 30 up to 180 days.

26. In a method for the controlled delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the fertilizer according to claim 7, 8 or 9, whereby the nutrient flow first begins after a waiting period from 30 up to 180 days.

27. In a method for the controlled delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the fertilizer according to claim 11, 12 or 13, whereby the nutrient flow first beings after a waiting period from 30 up to 180 days.

28. In a method for the controlled delivery of nutrients for plants in the soil of the type in which fertilizers are placed in the soil, the improvement comprising employing the fertilizer according to claim 18, 19 or 20, whereby the nutrient flow first begins after a waiting period from 30 up to 180 days.

29. A method of promoting the development of crop plants in a crop area, wherein the crop area is treated with a fertilizer as claimed in claim 1.

30. A method as claimed in claim 29, wherein a single treatment of the crop area is carried out at the start of the crop plants' growth with an amount of the fertilizer that is sufficient for the crop plants unill they are fully developed.

31. A method as claimed in claim 29, wherein the treatment is carried out before the crop plants are sown in the crop area.

32. A method of promoting the development of a living plant, wherein the area in the vicinity of the living plant is treated with a fertilizer as claimed in claim 2, 3 or 4.

33. A method of promoting the development of a living plant, wherein the area in the vicinity of the living plant is treated with a fertilizer as claimed in claim 5, 6 or 7.

34. A method of promoting the development of a living plant, wherein the area in the vicinity of the living plant is treated with a fertilizer as claimed in claim 8, 9 or 10.